#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#define MAXSIZE

int main(void)
{
	int  fd, size, len;
	char *buf="Hello! I'm writing to this file!";
	char buf_r[10];
	len = strlen(buf);
	/*首先调用open函数，并指定相应的权限*/
	if((fd = open("./testFile", O_CREAT | O_TRUNC | O_RDWR,0666 ))<0)
	{
		perror("open:");
		exit(1);
	}
	else
	{
		printf("open file:testFile %d\n",fd);
	}

	/*调用write函数，将buf中的内容写入到打开的文件中*/
	if((size = write(fd, buf, len)) < 0)
	{
		perror("write:");
		exit(1);
	}
	else
	{
		printf("Write:%s\n",buf);
	}

	/*调用lsseek函数将文件指针移到文件起始，并读出文件中的10个字节*/
	lseek( fd, 0, SEEK_SET );
	if((size = read(fd, buf_r, 10))<0)
	{
		perror("read:");
		exit(1);
	}
	else
	{
		printf("read form file:%s\n",buf_r);
	}

	if( close(fd) < 0 )
	{
		perror("close:");
		exit(1);
	}
	else
	{
		printf("Close hello.c\n");
	}
	
	return 0;
}
